The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A transmission may receive input torque from an engine of a vehicle and/or one or more electric motor/generators (e.g. in a hybrid vehicle) and provides output torque to a driveline. For example, the transmission selects between various gear configurations (i.e., shifts) to provide a particular output torque to the driveline in response to the input torque.
The transmission includes one or more clutches. The clutches selectively engage and disengage input and output shafts of the transmission to manage rotational speed and torque differences between the shafts. The transmission actuates the clutches to perform a shift between gear configurations (i.e. to provide a desired gear ratio).
Shifting from one gear ratio to another typically includes releasing (i.e. disengaging) an off-going clutch or clutches associated with a current gear ratio, applying (i.e. engaging) an on-coming clutch or clutches associated with the desired gear ratio, and/or maintaining one or more currently engaged clutches. For example, a shift may be executed by deactivating a single off-going clutch, activating a single on-coming clutch, and in some cases holding (i.e. maintaining) a third clutch for both the current and desired gear ratios. In other arrangements, multiple on-coming and\or off-going clutches may be actuated.